SLC 8x42 vs SFL 8x40 - without killing either …
Soon after the SFL came out, I thought: this is Zeiss‘ SLC - like the SLC for Swaro, the SFL is positioned in the second rang behind the top models, and like the SCL, the SFL early on got very good ratings.
Both are in my view fabulous binoculars, and if I prefer one over the other, that has nothing to do with „better“ or „worse“ and everything with personal preferences.
A few numbers to start:
Eye relief and effective/usable eye relief are identical: 18 mm and 15.5 mm, respectively. Both should work well with most glasses.
RFOV is 8 degress for the SFL and 7.8 for the SLC. Almost the same, I could only detect a slight difference when both binos were mounted side by side. Even more so perhaps since the SLC shows a slightly larger AFOV than the SFL (61 vs 60 degrees - both numbers measured myself). Reason: see below under distortion.
Minimum focus distance: excellent 1.45m for the SFL, mediocre 3.5m for the SLC (both measured).
Focus speed: much, much faster in the SFL than the SLC (from 3m to infinity: SFL 180 degrees, SLC 580 degrees rotation of the focus wheel – both measured).
Excess travel beyond infinity: very good for both (6.5 resp. 6 dpt - estimate).
The SFL weighs 710g with eyepiece covers and strap, the SLC 905g (both measured); the difference is substantial.
As for the „softer“ criteria:
As different as the two binos may be, I consider the finish and build quality as well as the haptics about equal in both. Grip in wet conditions, balance and the ergonomics, esp. with regard to the position of the focus wheel (see pic), are clearly better in the SFL.
Similarly regarding the eye cups and the diopter adjustment mechanism: the mechanics work quite differently, but both binos have in my view quality solutions.
Beside the focus speed, the very smooth and precise focusing of the SFL is a step ahead of the (after an earlier repair) still somewhat noisy focus of the SLC. The difference in focus speed is huge: the SFL has one of the fastest focusers I know, the SLC one of the slowest. Depending on usage, both can have advantages and disadvantages. For me, the SFL is too fast, the SCL too slow, ideal would be something in between.
And then the optics:
Field of view and off-axis sharpness are for my eyes very comparable, and the same holds true for CA correction (again, for my eyes!).
Color fidelity is a bit better in the SFL, although only by a small margin. The image of the SLC appears just a tiny bit warmer.
Both binos exhibit little globe effect, the SLC even less than the SFL. That is the result of clearly more pronounced rectilinear distortion of the SLC, which some will probably like and some not (and that’s why measured AFOV is still a useful number, because it takes into account the distortion which the simple formula doesn’t).
No big difference as far as I could see regarding stray-light, spikes etc. However, when observing bright lighting on a football field at night, the SFL let me distinguish the individual spotlights in the beamers even more easily than the SLC, which testifies to the quality of the Zeiss (Kamakura?) optics.
Last point: central sharpness, contrast, and what I would combined name “image brilliance”. Here, the SLC is ahead in my eyes, it has an incredibly brilliant image, but without the almost painful sharpness of the EL SV. To be sure I am not dreaming, I briefly (re)confirmed on the USAF 51 that the SLC with a 4x and a 6x booster exhibits more details than the SFL (that is not to be taken as the final truth, just an indication, the USAF-test is in black and white, and the world isn’t black and white) and is in that sense “sharper” than the SFL.
To conclude, I find both the SFL and the SLC superb „overall packages“. The one factor that lets me tip the balance in favor of the SLC is its image brilliance that I have hardly ever found in other binoculars. Most probably just a personal perception that others will not share. Over the years, my assessment of many binoculars has changed as I age, but the SLC still impresses me as it did when I first got it. Hard to describe really whether it‘s the specific combination of color tone, sharpness, contrast, and perhaps other factors, I just prefer the SLC‘s image over most other same size binos. For me, the SFL‘s image is great, the SLC’s unbeatable.
fwiw Canip